The present invention relates generally to internal combustion engines and, more particularly, to devices for separating certain liquid portions from certain vapors emitted by an internal combustion engine or the like.
During the operation of an internal combustion engine (e.g., a gasoline powered automobile engine), a small portion of the air-fuel mixture introduced into each combustion chamber escapes into the crankcase of the engine block by passing around the piston rings during the compression stroke, just before combustion. In a like manner, immediately after combustion, a small amount of the gases resulting from combustion is forced past the piston rings and into the engine crankcase. These gases, commonly known as blow-by gases, collect in the crankcase and are subsequently directed into the intake manifold, as explained below.
Approximately 80% of all blow-by gases originate from uncombusted air-fuel mixture, while the remaining 20% consists of combustion products, including water vapor, carbon dioxide, carbon monoxide and oxides of nitrogen. However, during engine operation, oil vapors continuously rise from heated engine lubricating oil and mix with the blow-by gases. In addition, when an engine has not been running for some time, it has been found that a small amount of fuel vapors will enter and collect in the crankcase.
The presence of the blow-by gases and the fuel and, particularly, oil vapors (hereinafter referred to collectively as "crankcase vapors") in the crankcase can cause the formation of various deposits and acids which adversely affect engine life and performance if allowed to remain in the crankcase for extended periods of time. In addition, if the crankcase vapors are improperly vented, not only can they cause poor engine performance but they can also have an adverse impact on the environment.
In order to eliminate the crankcase vapors safely and efficiently, modern internal combustion engines incorporate a positive crankcase ventilation ("PCV") system which directs the crankcase vapors from the crankcase to the intake manifold for introduction into the combustion chambers. The PCV systems generally include a hose (about 3/8" to 5/8" in inner diameter) which communicates the crankcase with the intake manifold with an air flow control valve, or PCV valve, in the flow path of the hose for regulating the flow of air into the intake manifold according to either the amount of the intake manifold vacuum or the amount of pressure or vacuum in the engine crankcase.
Although conventional PCV systems have been effective in removing crankcase vapors and introducing them into the intake manifold for combustion, they have the disadvantage of also allowing the introduction of certain liquid vapor contaminents (particularly the heavier, non-combustible oil vapors) contained in the crankcase vapors into the combustion chambers. The liquid contaminants can interfere with the combustion process causing poor engine performance and creating exhaust emissions which have undesirable effects on the environment.
Many crankcase emission control devices have been proposed for preventing the liquid contaminant from reaching the intake manifold and the combustion chambers during engine performance. Such devices, however, utilize filters or valve means which are expensive to produce, and difficult and cumbersome to use, or which interfere with the vapor flow in such a way as to be undesirable for use in an internal combustion engine.
U.S. Pat. No. 4,136,650, for example, discloses a filter device connected between the PCV valve and the intake manifold. The device includes a housing which contains a filter element, such as wool, for filtering the crankcase vapors and an air check valve for returning oil collected in the bottom of the filter to the crankcase. Although this filter device may operate adequately to separate liquid and solid contaminants from the vapor passed through the filtering element, there is the danger that the filtering element will become clogged with contaminants and thereby prevent, or at least impede, further gas flow through the PCV hose. As a result, the spark plugs of the engine will likely begin to foul and the air-fuel mixture will require enrichment in order to offset the loss of power, thereby increasing exhaust emissions due to the presence of unburned vapors and decreasing gas mileage as a result of incomplete combustion. In addition, the filtering element will require replacement, adding expensive servicing and material costs to the use of the device.
Other devices proposed for minimizing the amount of contaminants entering the intake manifold similarly utilize filtering means such as activated charcoal for absorbing crankcase vapors and other liquid and solid contaminants (U.S. Pat. No. 3,831,353) or alumina for absorbing phosphorus-containing compounds (U.S. Pat. No. 4,381,755). By and large, such devices encounter the same problems mentioned above.
Accordingly, it is a principal object of the present invention to provide a new and improved crankcase emissions device for removing liquid vapors from the crankcase emissions of an internal combustion or like engine. In addition, it is an object of the invention to provide such a crankcase emmissions device which enables the removed liquid vapors (particularly oil vapors) to return, in liquid form, back to the crankcase of the engine.
Another object of the present invention is to provide a new and improved crankcase emissions device which removes liquid contaminants from the crankcase vapors yet allows the remainder of the crankcase vapors to flow into the intake manifold of the engine for combustion.
A further object of the present invention is to provide a crankcase emissions device for removing liquid contaminants from the crankcase that pass to the intake manifold to prevent the engine spark plugs from being fouled by non-combustible residues.
It is yet a further object of the invention to provide a new and improved crankcase emissions device which decreases exhaust emissions by allowing the gas portion of crankcase vapors to flow into the intake manifold for complete combustion and the liquid portion, particularly oil, to return, as liquid, back to the crankcase.
It is also an object of the present invention to provide a new and improved crankcase emissions device which removes the liquid portion from the crankcase vapors without requiring any filter or like elements which would necessitate periodic replacement. In addition, the invention provides a crankcase emission device which is compact in size, simple and economical to fabricate, easy to install and needs no maintenance or servicing. Furthermore, the present invention makes it possible to save significant quantities of engine oil, particularly in diesel engines, reduce engine emissions, improve engine performance and mileage and reduce engine wear.
The foregoing and other objects and advantages of the invention will be apparent to those skilled in the art from the following detailed description when taken in conjunction with the accompanying drawings.